Equipment for muscular strengthening and rehabilitation in water

ABSTRACT

Equipment for muscular strengthening and rehabilitation in water comprising a mass of spongy material made of polyvinyl foam preferably with a substantially closed ring annular shape, with a central coaxial through hole. In a preferred embodiment of the invention the above-mentioned ring has a thickness ranging from 2 cm to 5 cm, an external diameter ranging from 9 cm to 15 cm and an internal diameter ranging from 4 cm to 5 cm. Preferably, the inner surface of said ring has an irregular profile. 
     In a different embodiment the equipment has a prismatic shape, substantially parallelepipedal, provided with two large opposite frontal surfaces, substantially rectangular, separated by at least four lateral surfaces, each smaller than one of said frontal surfaces, and comprises two open through cavities on said pair of frontal surfaces. Preferably, the above-mentioned parallelepiped has a length ranging from 9 cm to 15 cm, a width ranging from 9 cm to 15 cm and a thickness ranging from 2 cm to 5 cm. 
     In a further embodiment the equipment has the form of a dumbbell, substantially comprising a section of tube provided on each end with a polyvinyl annular element.

FIELD OF APPLICATION OF THE INVENTION

The invention concerns the sector of equipment for muscular strengthening and rehabilitation in water of athletes and persons who have had accidents, surgery or disabling illnesses and require physiotherapeutic rehabilitation to strengthen or recover muscular performance.

The advantages of muscular activity in water, i.e. in a medium which resists the movements of the limbs, obliging the muscles to make certain efforts to carry out specific movements, consequently strengthening the muscles to achieve improved athletic performance or to recover functions that have been damaged, or even lost, following accidents and/or illnesses, have been known for some time.

Most people have experienced the greater effort required to walk in shallow water (just above the knees) compared to walking on dry ground, all other conditions being equal, and have appreciated the consequent benefits of improved muscle tone.

For physical exercise to be truly productive, the resistance of the water to the limb involved must be increased, incrementing the workload either with equipment that increases frontal resistance to forward movement of the limb or with weighted loads. These are the methods that have been used so far, i.e. making the muscles involved work with a greater effort, since the desired recovery or strengthening of muscle tone is the result of this increased effort.

So far, to determine and control the overload applied to the limbs during exercises in water, various technical means have been used such as elastic resistance bands, flippers, paddles, weighted equipment and elements made of spongy material, in particular polyethylene foam. Said means dynamically obstruct the movement of the limb, requiring the movement of a greater mass of water than with the movement of the limb only, or directly apply a weight to the limb involved in the movement.

The Applicant has realised that said technical means do not best meet the real needs of a person doing this type of training in water. In fact, the aim of every physical exercise is to improve the strength and power of a specific muscular sector, whereas the above-mentioned equipment, during each exercise, also involves, within the muscle sectors concerned, fibres which have no reason to intervene in relation to the muscle sector to be exercised, but are obliged to intervene to compensate either the weight force or the buoyancy of the component material of said equipment. Flippers and paddles are provided with a flat surface which moves a variable quantity of water in relation to the direction of movement of the equipment. Clearly, the quantity of water moved is of the maximum value when the movement occurs in a direction perpendicular to the surface of the equipment, and of the minimum value with movement parallel to the surface of the equipment. The shifting of the mass of water caused by the movement, since said quantity does not have a constant value with variation of the movement, poses problems of loss of resistance when movements are performed according to a combination of different directions.

Weighted equipment (heavier than water) requires part of the muscles to be used to overcome the weight force with an upward thrust. Foam equipment with high buoyancy requires a considerable downward effort to overcome said buoyancy.

In addition to this, equipment made of spongy material deteriorates very quickly with use and has to be replaced.

According to the intuition of the Applicant, all the problems highlighted can be solved by using, in a new and non-obvious way, a special material in construction of the equipment for muscular strengthening and rehabilitation in water; said material, although not completely new, has never been used for this purpose since its potential has never been understood by the persons skilled in the art.

The invention therefore concerns equipment for muscular strengthening and rehabilitation in water comprising a mass of spongy material characterised in that said material is open cell polyvinyl foam.

Further characteristics and advantages of the invention will become clear from the detailed description of some preferred but not exclusive embodiments of equipment according to the present invention of which the accompanying drawings are provided only for illustrative and therefore non-limiting purposes, in which:

FIG. 1 illustrates, in a perspective view, the equipment of the invention, in a first preferred embodiment, particularly suited to be fitted on ankle and wrist;

FIG. 2 illustrates, in a perspective view, the equipment of the invention in a second embodiment, particularly suited to be gripped by hand;

FIG. 3 illustrates, in a perspective view, the equipment of the invention in a third embodiment, particularly suited to be gripped as a dumbbell;

FIG. 4 illustrates, in a perspective view, the equipment of the invention in a fourth embodiment, suited to be worn on the ankle or wrist;

FIG. 5 illustrates the equipment of the invention of FIG. 1 fitted on the lower limb of a user;

FIG. 6 illustrates schematically an individual performing an aqua fitness and/or rehabilitation exercise in water with equipment according to the known art, made of polyethylene foam;

FIG. 7 illustrates schematically an individual performing an aqua fitness and/or rehabilitation exercise in water with equipment according to the known art, made of weighted material;

FIG. 8 illustrates schematically an individual performing an exercise similar to the one in FIGS. 6 and 7, with equipment according to the invention made of polyvinyl foam;

FIG. 9 illustrates schematically an individual performing a swimming strengthening exercise with an ankle band made of foamed material, according to the known art;

FIG. 10 illustrates schematically an individual performing an exercise equivalent to the one in FIG. 9 with a weighted ankle band, according to the known art;

FIG. 11 illustrates schematically an individual performing an exercise equivalent to the one in FIGS. 9 and 10 with polyvinyl foam equipment according to the invention.

FIG. 1, as said, illustrates in a perspective view the equipment according to the invention in a first preferred embodiment consisting of a basically annular element made of open cell polyvinyl material. More precisely, this material is defined and otherwise known on the market as P.V.A. (polyvinyl alcohol). This type of material has the capacity to absorb water like a sponge or polyethylene foam but, unlike the foamed material, polyvinyl (P.V.A.), even if open cell, absorbs a volume of water substantially equal to its own volume. This means that when it is immersed in water, it absorbs a quantity of water substantially equivalent to the volume of water moved due to its own volume and therefore it is not substantially subject to buoyancy or gravity, i.e. to that of its own weight. In other words, it has a neutral behaviour with respect to the liquid in which it is immersed. A practical example will clarify this aspect. If we take two geometrically identical elements, for example two rings made of polyvinyl and polyethylene foam respectively, and place them on a liquid surface, the polyvinyl ring remains immersed in the liquid until it is arranged with its upper surface coplanar with the surface of the liquid, while the polyethylene ring floats on the liquid surface, remaining completely emerged. In a second experiment the two geometrically identical elements were compared, one in polyvinyl, according to the invention, and the other in polyethylene foam, according to the known art, identifying the following characteristics:

POLYETH. ELEMENT POLYVINYL FOAM Weight of dehydrated element 45 g 13 g Weight of hydrated element 330 g 13 g Sinking weight 40 g 365 g Surfacing time 4.10 sec. 0.80 sec. (from a depth of 60 cm)

In the preceding description, reference is always made to water but this obviously does not limit the type of liquid used; the specific behaviour and differences between said behaviours are maintained whatever the type of liquid used. However, it is also obvious, and known, that training and physiotherapy are performed in pools filled with water and not with other possible liquids.

It has already been said that the equipment according to the invention, in a first preferred embodiment, consists of a basically annular element. Basically annular means that it can also be hexagonal, square, rhombic, octagonal or of other similar shapes, in addition to perfectly annular. For the sake of simplicity of description, we will refer to this element as a ring. FIG. 1 illustrates an annular element 1 of substantially square shape, rounded with smooth edges according to an octagonal profile. Said element is a closed ring with a central through hole 2, designed to allow fitting of the ring (FIG. 5) on the limb in question. Clearly, in order to strengthen the leg muscles, the equipment must be fitted on the ankle, and to strengthen the arm muscles, it must be fitted on the wrist or the hand. Preferably, the external diameter of the above-mentioned ring ranges from 9 cm to 15 cm, the diameter of the central hole ranges from 4 cm to 6 cm and the thickness ranges from 2 to 6 cm. In particular, in the embodiment of FIG. 1 the width “a” of the element, identical according to two directions orthogonal to each other, is 13 cm, the diameter “d” of the central hole is 5 cm and the thickness “s” is 3 cm. Preferably, the surface of the hole 2 is irregular, for example knurled or in any case provided with ridges projecting radially towards the inside. The purpose of said shape is to ensure the stability of the position of the ring on the limb during the physical exercise since the dimensions of the ring when soaked with water vary, albeit modestly, with respect to the dimensions of the ring when dry.

In particular, the dimensions of the annular element of FIG. 1, in the dehydrated condition, are 11 cm×11 cm×2 cm, diameter of the hole 4,6 cm, whereas in the hydrated condition they become 13 cm×13 cm×5 cm, diameter of the hole 5 cm.

In a different embodiment (FIG. 2) the equipment according to the invention has a prismatic substantially parallelepiped shape, provided with two large opposite frontal surfaces 3, substantially rectangular, separated by at least four lateral surfaces 4 each smaller than one of said frontal surfaces, and comprises two open through cavities, the windows 5, on said pair of frontal surfaces. Preferably, for the sides “b” and “c” and the thickness “s” the same dimensional limits apply as those already established for the ring 1. Preferably the opposite sides “b” have a different length from the opposite sides “c”. This equipment is fitted on the limb by progressively passing the limb through both the windows 5.

In a third embodiment (FIG. 3) the equipment according to the invention has the form of a dumbbell; it substantially comprises a section of tube 6 provided on each end of the equipment 7, in open cell polyvinyl foam, according to the invention, preferably annular in shape. More precisely, the tube 6 is made of the lightest material possible, while ensuring the necessary strength and rigidity, and the equipment 7 is fitted on said tube in a manner coaxial to the same. The maximum length “I” of the dumbbell is preferably between 24 cm and 30 cm, whereas for the equipment fitted on the ends of the tube preferably the same dimensional limits apply, for the external diameter “D” and for the thickness “s”, already illustrated previously with reference to FIG. 1.

Said equipment can be positioned on the tube in modular multiples, i.e. more than one on each end, according to the muscular stress required.

In a further embodiment (FIG. 4) the equipment 8 according to the invention has a substantially open annular shape, i.e. it can be opened and closed to facilitate fitting of the equipment on the limb in question.

To guarantee closing of the equipment on the limb during the exercise, the above-mentioned equipment is preferably provided on its outer lateral surface with a closing band 9 for said ring.

The invention offers important advantages.

FIG. 6 illustrates schematically the lower limb of a person who wishes to strengthen his/her muscles or who requires limb rehabilitation. The exercise consists in rhythmically raising the leg to a semi-extended frontal position, with the person partially immersed (up to the chest) in water. A device according to the known art consisting of a polyethylene foam ring is fitted on the ankle of the limb. In this exercise, with the traditional equipment, to obtain the movement in question, the muscles of the limb must intervene, splitting the muscle fibre contraction requirement in 2 directions. One part of the fibres has to counter the natural resistance of the water to the movement of the leg and volume of the element connected to it, throughout the leg movement, developing a force “F1”.

The other part of the fibres has to counter the buoyancy “R3”, acting on the polyethylene foam element which under said force tends to move rapidly upwards, developing an antagonist force “F2”. Therefore, F2 is a force of no use to the movement required, since it serves only to counter the buoyancy of the ankle band, but this interference prevents the muscle from contracting all the fibres in one single direction with the maximum intensity possible.

In FIG. 7 the limb is fitted with a weighted open ring device according to the known art, which is subject to the effect of the weight force, represented by the resistance “R5”. Also in this case the muscles of the limb have to develop an additional force “F4” to overcome the above-mentioned resistance, with the same consequences as illustrated above in FIG. 6, but inverted since in this case the limb has to overcome, with a large quantity of fibres, the interference of the weight “R5”. On the other hand, when the limb is fitted with the equipment according to the invention, for example pair of closed rings, as in FIG. 8, the only force at play is the force “F1”, i.e. only and exclusively the frontal resistance to the forward movement of the masses, i.e. leg and ankle band, in the water.

Therefore, the movement is no longer subject to the weight and buoyancy variables, and consequently the muscles can contract all the fibres in a unitary manner to obtain the maximum effort with the greatest intensity and power possible. This optimally implements the principle already expressed in the art (Harre) but never achieved, according to which: to improve the force and power of a specific muscle sector responsible for a specific movement, we must work on the ability of our muscle to recruit all, or the majority, of the possible fibres of that specific muscle in one single contraction. To do this, we must work on the pure movement, freeing all the muscle fibres from forces external to the movement, which would distract the muscle fibres from that movement.

The same considerations apply in the case of a different type of exercise, illustrated in FIGS. 9, 10 and 11. With the known devices (FIGS. 9 and 10) the development of a force “F1” necessary to achieve a precise objective is always accompanied by the need to develop spurious forces “F2”-“F4” to balance the resistances “R3”-“R5” generated by the structure of the device.

The equipment according to the invention, due to its neutral behaviour with respect to the liquid in which it is immersed, allows the person doing the exercises to selectively develop only the muscles involved in performance of the specific muscle exercise, in the case illustrated (FIG. 11) a backward thrust of the foot, without waste of energy and interferences of other forces.

In the present description, all the possible structural and dimensional alternatives to the embodiments of the invention specifically described have not normally been illustrated, it being deemed not necessary to go into the construction details of the system of the invention since any person skilled in the art, after the instructions provided here, will have no difficulty in designing, choosing appropriate materials and dimensions, the most advantageous technical solution.

These variations are nevertheless understood to be included in the protective scope of the present patent, since said alternative forms per se can be easily derived from the description herein of the relation linking each embodiment with the result which the invention aims to achieve. 

1. Equipment for muscular strengthening and rehabilitation in water comprising a mass of spongy material, said material being open cell polyvinyl (P.V.A.) characterised in that said mass has shape substantially annular.
 2. Equipment according to claim 1, characterised in that said shape is a substantially closed ring.
 3. Equipment according to claim 2, characterised in that said ring has a thickness of between 2 cm and 5 cm, an external diameter of between 9 cm and 15 cm and an internal diameter of between 4 cm and 5 cm.
 4. Equipment according to claim 2, characterised in that the inner surface of said ring has an irregular profile.
 5. Equipment for muscular strengthening and rehabilitation in water comprising a mass of spongy material, said material being open cell polyvinyl (P.V.A.), characterised in that said mass has a prismatic shape, substantially parallelepiped, provided with two large opposite frontal surfaces, substantially rectangular, separated by four lateral surfaces each smaller than one of said frontal surfaces, and comprises two open through cavities on said pair of frontal surfaces.
 6. Equipment according to claim 5, characterised in that said parallelepiped has a length of between 9 cm and 15 cm, a width of between 9 cm and 15 cm and a thickness of between 2 cm and 5 cm.
 7. Equipment for muscular strengthening and rehabilitation in water characterised in that it has the form of a dumbbell, substantially comprising a section of tube provided at each end with one or more masses of open cell polyvinyl (P.V.A.) spongy material, with a substantially annular shape.
 8. Equipment according to claim 7, characterised in that said masses are fitted on said tube in a manner coaxial to the same.
 9. Equipment according to claim 1, characterised in that said substantially annular shape is a form which can be opened and closed.
 10. Equipment according to claim 9, characterised in that said substantially annular shape is a ring shape provided on its outer lateral surface with a closing band for said ring. 